UC-NRLF 


3D  357 


THE  DEATH  CAIiAS  SPECIES,  ZYGADENUS  PANICULATUS 
AND  Z.  EL3GANS,  AS  POISONOUS  PLANTS. 

BY:   G.  Dwight  Marsh 
D.S.D.A.  Bui.  1012          April  17,  19E2 


.  -  Forestry .  M  am  latff  ar? 


Agric.  -Hqresiry.  Main 


UNITED  STATES  DEPARTMENT  OF  AGRICULTURE 


BULLETIN  Nov  1012 

Contribution  from  the  Bureau  of  Animal  Industry 
JOHN  R.  MOHLER,  Chief 


rashington,  D.  C. 


PROFESSIONAL  PAPER 


April  17,  1922 


HE    DEATH    CAMAS    SPECIES,    ZYGADENUS   PANICULATUS 
AND    Z.    ELEGANS,    AS   POISONOUS    PLANTS. 

C.  DWIGHT  MARSH,  Physiologist  in  Charge  of  Investigations  of  Stock  Poisoning  by 
Plants,  and  A.  B.  CLAWSON,  Physiologist,  Pathological  Division. 


'urpose  and  scope  of  paper 

Zygadenus  paniculatus 

Description  and  distribution  of  plant . . . 

Experimental  feeding 

Mscussion  and  results 

Symptoms 

Duration  of  symptoms 

Time  required  to  produce  symptoms  . . . 

Toxic  and  lethal  dosage 

Zygadenus  elegans 

Description  and  distribution  of  plant 

Experimental  feeding 


CONTENTS. 

Page. 

2 
2 

3 

10 
10 
12 
13 
13 
16 
16 
17 


Page. 

Discussion  and  results 20 

Symptoms 20 

Duration  of  symptoms 2] 


Time  required  to  produce  symptoms.. . 

Results  of  autopsy 

Toxic  and  lethal  dosage 

Comparative  toxicity  of  Z.  gramineus,  Z. 

paniculatus,  and  Z.  elegans 

Z.  elegans  not  especially  dangerous  for 

sheep 

Summary 


PURPOSE  AND  SCOPE  OF  PAPER. 

In  Bulletin  125,  United  States  Department  of  Agriculture,  page 
55,  the  following  statement  was  made  with  regard  to  the  comparative 
>xicity  of  different  species  of  Zygadenus:1 

In  the  course  of  the  experiments  four  species  of  Zygadenus  were  used — Z.  venenosus, 
' .  elegans,  Z .  paniculatus,  and  Z .  coloradensis — by  far  the  greater  part  of  the  work  be- 
lone  with  Z.  venenosus.  The  number  of  experiments  with  Z.  elegans  and  Z.  pani- 

ilatus  was  very  small,  and  the  material,  especially  in  the  case  of  Z.  paniculatus,  had 

m  shipped  a  long  distance,  so  that  there  was  some  question  of  the  water  content 
!theplant.  Apparently,  however,  Z.  elegans  smd  Z .  paniculatus  do  not  differ  materially 

toxicity  from  Z.  venenosus.  Z.  coloradensis,  however,  produced  no  toxic  effects 
whatever,  with  the  exception  of  slight  symptoms  in  one  sheep,  although  the  plant 
^as  fed  in  quantities  several  times  as  great  as  the  toxic  dose  of  Z .  venenosus. 

It  is  evident  that  in  the  feeding  of  cattle  with  Z.  coloradensis  at  Mount  Carbon  in 
[909,  the  results  of  which  are  given  in  Table  I,  the  quantities  fed  were  too  small  to 
produce  results,  even  if  the  plants  were  as  poisonous  as  Z.  venenosus.  In  the  experi- 

?nt  of  1910,  however,  a  large  quantity  was  fed,  and  sufficiently  large  quantities  in 

igle  days' to  produce  symptoms  of  poisoning  if  the  plant  were  as  toxic  as  Z.  venenosus. 

Most  of  the  work  reported  in  Bulletin  125  was  on  the  species  of 
Zygadenus  growing  in  the  Yellowstone  Valley,  Montana,  which 

1  Zygadenus,  or  Death  Camas  by  C.  Dwight  Marsh,  A.  B.  Clawson,  and  Hadleigh  Marsh,  Bulletin  125, 
Jnited  States  Department  of  Agriculture,  1915. 
67283°— 22— Bull.  1012 1 


•  •  J 


2  BULLETIN    1012,    U.    S.    DEPARTMENT    OF   AGRICULTURE.  ( 

at  that  time  was  deterimried'by  sy*£t££n&4j<;  Ijotanists  as  Z.  venenosus. 
Later  systematic  work  has"  s'h'own*  that  "Ine "Species  used  was  not  the 
true  venenosus,  but  w/is:  %*.•$$  tniri£us.  \  Q[  ^tfte  other  species  used. 
Z.  elegans  and  Z.  cotoradensls' are  so  "closely 'allied   that   they  are 
considered  by  many  botanists  as  not  specifically  distinct.     There  is 
no  question,  however,  of  the  specific  distinction  between  Z.  granti- 
neus,  Z.  elegans,  and  Z.  paniculatus.     From  further  work  it  seemed 
probable  that  there  was  a  much  greater  difference  in  toxicity  of  the 
species  than  was  apparent  at  the  time  Bulletin  125  was  published, 
and  it  became  a  matter  of  considerable  importance  to  determine  the 
comparative  toxicity  of  the  different  forms. 

All  these  species  are  so  closely  allied  that  they  are  not  likely  to  be 
separated  by  anyone  who  has  not  a  fairly  good  knowledge  of  botany. 
It  follows,  of  course,  that  ordinarily  all  these  forms  are  grouped  under 
the  term  u  death  camas"  without  perception  of  the  difference  be-    I 
tween  the  species.     It  is  a  matter  of  much  scientific  and  practical   • 
interest  to  know  how  they  differ. 

Z.  paniculatus  is  the  most  widely  distributed  and  is  the  nnst 
common  form  of  death  camas  in  the  intermountain  region  andinh  H 
part  of  the  western  slope.     Z.  elegans  is  not  so  abundant  but  is  the   . 
common  species  on  the  higher  mountain  ranges  of  the  West.    B  th 
Z.  elegans  and  Z.  paniculatus  grow  in  considerable  quantity  in  the 
neighborhood   of   the   Salina   Experiment   Station,   Utah,   where  a 
somewhat  extended  study  of  the  plants  has  been  made.     The  proof 
that  these  species  are  either  more  or  less  toxic  than  Z.  gramiwis, 
which  grows  in  Montana,  would  be  of  very  great  practical  importance 
to  the  stockmen  w^ho  use  the  ranges  where  these  plants  are  found,    j 

The  experimental  work  was  conducted  on  the  same  general  lines  as 
the  work  in  Montana,  and  the  results  have  proved  to  be  of  consider- 
able importance.  Still  further  work  is  necessary  on  the  species  of  • 
this  genus,  but  the  results  obtained  regarding  these  two  species  are 
definite  and  conclusive.  All  the  work  here  reported  was  done  on 
plant  material  collected  in  Utah.  Inasmuch,  however,  as  experience 
with  poisonous  plants  indicates  that  difference  in  locality  has  little 
effect  on  the  degree  of  toxicity,  the  conclusions  reached  here  un- 
doubtedly will  apply  equally  well  to  these  species  wherever  they  may 
be  found.  It  may  be  added  that  Zygadenus  intermedius,  on  which 
work  has  been  done  by  other  authors,  is  considered  by  systematist 
as  being  identical  with  Zygadenus  gramineus. 

ZYGADENUS  PANICULATUS. 

DESCRIPTION  AND  DISTRIBUTION  OF  THE  PLANT.* 

Zygadenus  paniculatus,  shown  in  Plate  I,  is  an  erect  perennial  her 
with  leafy  stems  arising  from  fibrous-coated  bulbs.     The  linear  leave 


2  The  description  of  Z.  paniculatus  and  its  distribution  was  prepared  by  W.  W.  Eggleston,  of  the  Bt 
of  Plant  Industry.    Mr.  Eggleston  has  made  a  detailed  study  of  the  genus  Zygadenus. 


DEATH   CAMAS   SPECIES,   ZYGADENUS  PANICULATUS. 


are  scythe-shaped,  all  s/ieatMngVrpughi^kon  both  sides,  rather  thick, 
6  to  12  inches  long,  and  one- tbinl  to  ^two-thirds  of  an  inch  wide. 
The  stems  are  stout,  erect ,  and*!  'to  2-J  feet  high.  The  flowers  are  in 
panicled  racemes,  and  consist  of  six  segments  with  membranous 
bracts;  the  upper  segments  are  deltoid,  acute,  or  acuminate,  with  a 
short  claw  and  glands  at  base  not  definitely  margined.  The  flower 
segments  are  one-sixth  to  one-fourth  of  an  inch  long  and  are  free 
from  the  3-celled  ovary.  The  ovary  is  cylindrical  and  one-half  to  1 
inch  long.  The  stamens  are  raised  above  the  flower  segments. 

This  plant  is  largely  confined  to  the  Great  Basin.  (Fig.  1.)  Its 
known  range  is  from  the  British  Columbia  line  in  the  Cascades  south, 
in  Washington,  along 
the  eastern  side  of  the 
Cascade  Range  to 
northwestern  Cali- 
fornia, where  for  a 
distance  it  crosses  to 
the  western  side  of  the 
Sierra  Nevadas.  It 
follows  the  eastern 
slope  of  the  Sierra 
Nevada  Mountains  to 
the  southern  extremity 
of  Nevada.  It  ranges 
eastward  across  south- 
ern Washington  and 
central  Idaho  to  west- 
ern Montana,  thence 
across  southwestern 
Wyoming  to  north- 
eastern New  Mexico 
and  northern  Arizona. 

It       ascends       On       the  FIG'  1'~ Distribution  of  Zygadenus  paniculatus. 

British  Columbia  line  to  about  7,000  feet  and  in  the  Wasatch  Moun- 
tains to  about  8,500  feet.  In  California  it  is  found  above  2,700  feet. 
Its  best  habitat  is  the  dry  gravelly  ridges  of  the  juniper-pifion-oak  belt. 
Because  of  the  wide  range  of  conditions  under  which  the  plant 
grows,  its  time  of  flowering  varies.  It  is  said  to  blossom  in  California 
from  April  to  June.  Near  the  Salina  Experiment  Station,  Utah, 
where  it  grows  at  an  altitude  of  more  than  8,000  feet,  it  does  not 
blossom  until  June  and  is  in  seed  the  last  of  the  month. 

EXPERIMENTAL  FEEDING. 

In  1919,  1920,  and  1921,  7  experimental  feedings  of  Z.  paniculatus 
were  made  on  cattle  and  44  on  sheep.  Table  1  gives  a  summary  of 
these  experiments. 


BULLETIN    1012,    V.    S.    DEPARTMENT    OF   AGRICULTURE. 


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DEATH    CAMAS    SPECIES,    ZYGADENUS  PANICULATUS. 


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6 


BULLETIN   1012,    V.    S.    DEPARTMENT   OF   AGRICULTURE. 


TYPICAL    CASE    OF    SHEEP   002. 

Sheep  602  was  a  yearling  ewe,  weighing  at  the  time  of  the  experi- 
ment 71.5  pounds.     It  was  taken  into  the  corrals  on  June  29,  1920, 
and   kept   under   observation   until   the   experimental   feeding   was 
undertaken,  on  July  1. 

On  July  1,  at  11.15  a.  m.,  the  animal  was  given  by  balling  gun 
1.764  pounds,  per  100  pounds  of  animal,  of  leaves,  stems,  and  young 
fruit  of  Z.  pani-culatus.    At  2.30  p.  m.  the  animal  was  frothing  at  the 
mouth,  and  in  walking  reeled  from  side  to  side.     At  2.35  p.  m.  the 
weakness  was  most  pronounced  in  the  hind  legs.    This  weakness  gradu- 
ally increased  and  at  7.40  p.  m.  the  animal,  in  walking,  not  only  stag- 
_____  _    gered  but  dragged  the 

hind  feet.  The  con- 
dition remained  the 
same  during  the  even- 
ing. The  next  day, 
July  2,  at  6.38  a.  m., 
the  animal  was  still 
frothing  at  the  mouth 
and  apparently  some- 
what  nauseated, 
although  it  seemed 
somewhat  stronger 
than  during  the  pre- 
ceding evening.  Dur- 
ing the  day  its  con- 
dition did  not  change 
materially.  It  was 

.    A  *,, 

quiet  and  depressed 
and  weak,  but  not  very  sick.  The  last  observation  of  the  day  was 
made  at  4.15  p.  m. 

On  the  morning  of  July  3  the  animal  seemed  to  be  entirely  recov- 
ered. The  temperature  curve  is  shown  in  text  figure  2.  While 
there  were  variations  in  the  pulse  and  respiration,  the  changes  were 
not  significant. 

Sheep  602  may  be  considered  as  a  fair  type  of  animals  which  arej 
not  very  sick. 


FIG.  2.—  Temperature  curve  of  Sheep  602. 


TYPICAL    CASE    OF    SHEEP  569. 


Sheep  569  was  a  2-year-old  wether,  weighing  85.5  pounds  at  the 
time  of  the  experiment.  It  was  taken  from  the  pasture  into  the 
corrals  on  the  morning  of  July  8,  1920.  At  this  time  the  temper- 
ature was  103°  F.,  pulse  88,  respiration  32.  The  sheep  was  observed 
again  at  night,  and  on  the  morning  of  July  9.  At  9.35  a.  m.,  July  9, 
the  temperature  was  103°  F.,  pulse  96,  respiration  24.  At  2  p.  m. 
the  animal  was  given  by  balling  gun  0.661  pound,  per  hundredweight 
of  animal,  of  fruit  heads  of  Z.  pamculatus.  At  4.37  p.  m.,  the  animal 


DEATH    CAMAS   SPECIES,    ZYGADENUS  PAHICTJLATT7S.  7 

was  found  to  be  very  sick  and  in  some  pain,  with  irregular  respiration. 
There  was  a  pause  after  the  inspiration,  followed  by  »a  somewhat 
forcible  expiration.  The  animal  was  weak  and  soon  lay  down. 
At  4.46  p.  m.,  the  temperature  was  98.4°  F.,  pulse  96,  respiration  28. 
The  pulse  was4  fairly  strong  and  regular.  The  respiration  continued 
as  before.  At  this  time  the  sheep  was  frothing  at  the  mouth,  was 
much  depressed,  and  showed  weakness  in  the  hind  legs.  A  little 
later  the  respiration  was  found  to  be  very  rapid,  being  approximately 
200.  At  5.32  p.  m.,  the  animal  was  down,  evidently  had  been  strug- 
gling, and  was  unable  to  rise.  Plate  II,  figure  1,  shows  the  position 
the  animal  assumed  at  this  time.  From  then  until  about  6  p.  m., 
its  condition  remained  practically  unchanged.  The  temperature  at 
5.34  p.  m.  was  99.4°  F.,  and  the  respiration  40.  Most  of 
the  time  the  animal  was  fairly  quiet  but  unable  to  rise.  At 
o.57  p.  m.,  it  was  able  to  get  up  on  its  feet,  although  still  very  weak. 
Plate  II,  figure  2,  shows  the  attitude  assumed  at  this  tim,e.  The 
weakness  seemed  most  pronounced  in  the  forelegs.  About  6  p.  m. 
it  went  down  because  of  weakness  and  almost  immediately  got  up 
again,  the  weakness,  as  before,  being  most  pronounced  in  the  forelegs. 
From  7.20  until  11.13  p.  m.  it  was  lying  down  quietly,  most  of  the 
time  apparently  unable  to  rise.  At  11.13  p.  m.  it  was  breathing 
heavily  and  rather  noisily  at  the  rate  of  20  a  minute. 

On  July  10,  at  6.30  a.  m.,  it  was  in  about  the  same  posi- 
tion as  during  the  preceding  evening.  Plate  II,  figure  3,  shows  its 
attitude  at  this  time.  At  8  a.  m.,  while  still  lying  down,  it  was 
found  to  have  moved  across  the  pen.  At  8.40  a.  m.,  when  dis- 
turbed it  attempted  to  get  upon  its  feet,  but  was  unable  to  lift  the 
body  on  the  forelegs.  At  this  time  the  temperature  was  99.3°  F., 
pulse  112,  and  respiration  24.  These  observations  were  taken  just 
following  an  attempt  to  rise.  After  lying  quietly,  the  pulse  was 
about  100.  The  sheep  at  this  time  was  in  a  semicomatose  condition, 
with  the  eyes  half  closed,  but  roused  if  approached.  The  condition 
remained  much  the  same  during  the  rest  of  the  day,  and  the  evening. 
The  picture  Plate  II,  figure  4,  taken  at  2.50  p.  m.,  shows  very  well 
the  condition  of  the  animal.  The  coma  was  very  pronounced  during 
this  period.  At  midnight  the  animal  commenced  to  kick  and  went 
into  a  position  of  opisthotonos,  at  the  same  time  gasping.  Follow- 
ing these  spasmodic  movements,  which  could  hardly  be  called  con- 
vulsions, its  mouth  was  opened  during  the  expirations. 

On  July  11,  at  7.30  a.  m.,  it  was  found  lying  much  as  at  midnight, 
but  breathing  more  easily.  At  10.35  a.  m.,  the  temperature  was 
99.7°  F.,  pulse  120,  respiration  44.  The  pulse  was  weak  and  variable, 
and  the  respiration  somewhat  labored.  A  little  later  the  respiration 
was  too  fast  to  count.  The  condition  remained  the  same  during 
the  forenoon  and  evening.  At  4.15  p.  m.  and  at  5  p.  m.,  it  was 


8 


BULLETIX    1012,    U.    S.    DEPARTMENT   OF   AGRICVLTURE. 


8 


10      II       12      13       14      15 


/O3 


/02 


/O/ 


/oo 


99 


V 


given  hypodermic  ally  5  c.  c.  of  gin,  which  seemed  to  have  an  im- 
mediate but  temporary  effect  in  strengthening  the  action  of  the 
pulse.  No  change  was  noticed  during  the  evening,  except  that  at 
11.25  p.  m.,  the  pulse  was  found  to  be  distinctly  stronger  than 
earlier  in  the  evening. 

On  July  12,  at  8.30  a.  m.,  the  temperature  was  100.6°  F.,  pulse  116, 
and  respiration  16.  The  pulse  was  very  weak,  while  the  respiration 
was  deep  and  regular.  The  animal  appeared  brighter  than  during 
the  preceding  evening,  but  was  still  lying  down.  At  10.45  a.  m., 

the  sheep  was  raised 
up,  and  drank  3  or  4 
quarts  of  water.  It 
was  able  to  hold  itself 
up  for  two  or  three 
minutes,  but  soon  lay 
down  again.  The  ani- 
mal drank  again  at 
11.35  a.  m.,  and  at- 
tempted to  get  up  on 
its  feet,  but  was  un- 
able to  do  so.  At  3. 30 
p.  m.,  it  was  raised  up 
and  drank  more  water. 
The  temperature  at 
this  time  was  100.6° 
F.,  pulse  120,  and  respiration  12.  At  5  p.  m.,  it  was  offered  some 
green  forage,  and  ate  readily.  The  condition  continued  unchanged 
during  the  evening. 

On  July  13,  at  7  a.  m.,  the  sheep  was  raised  up  on  its  feet  and 
held,  and  then  it  became  able  to  stand  alone.  It  was  unable, 
however,  to  walk  without  falling.  The  legs  of  the  left  side  seemed 
weaker  than  those  of  the  right.  This  perhaps  was  due  to  the  fact 
that  during  the  period  it  was  lying  down  it  lay  upon  the  left  side. 
At  4.11  p.  m.,  the  temperature  was  101.6°  F.,  pulse  120,  respiration 
164.  The  pulse  was  fairly  strong  and  regular.  The  respiration  was 
short  but  regular.  At  this  time  the  animal  was  on  its  feet  although 
still  very  weak.  It  was  able  to  walk  out  into  a  large  corral  to  drink 
with  the  other  sheep. 

During  the  day,  July  14,  the  temperature  of  the  animal  was  higher, 
being  103.3°  F.  at  4.35  p.  m.  The  pulse  was  strong  and  regular  and 
the  respiration  became  more  normal.  The  sheep  was  quite  strono- 
and  able  to  get  about  and  eat. 

On  the  morning  of  July  15  the  animal  seemed  to  have  entirely 
recovered,  and  was  turned  into  the  pasture  with  the  other  sheep. 
Text  figure  3  shows  the  curve  of  temperature  during  the  illness 
of  the  animal. 


FIG.  3.— Temperature  curve  of  Sheep  569. 


Bui.  1012,  U.  S.  Deptrof  Agriculture. 


PLATE  I. 


ZYGADENUS  PANICULATUS.    PLANT  WITH  BULB  AND  FLOWERS. 


!ul.  1012,   U.  S.  Dept.  of  Agriculture. 


PLATE  II. 


FIG.  I.— SHEEP  569  AT  5.32  p.  M. 
JULY  9,  WHEN  POISONED  BY 
ZYGADENUS  PANICULATUS, 


FIG.  2.-SHEEP  569  AT  5.57  p.  M. 
JULY  9,  ABLE  TO  STAND,  BUT 
VERY  WEAK. 


FIG.  3.— SHEEP  569  AT  6.30  A.  M. 
JULY  10,  SHOWING  EXTREME 
WEAKNESS. 


FIG.  4.-SHEEP  569  AT  2.50  p.  M. 
JULY  10,  IN  CONDITION  OF  COMA. 


FIG.  5.— CATTLE  863  POISONED  BY 
ZYGADENUS  PANICULATUS,  IN  ACT 
OF  VOMITING. 


FIG.  6.— HORSE  137  POISONED  BY 
ZYGADENUS  PANICULATUS,  THE 
ATTITUDE  SHOWING  EXTREME 
DEPRESSION  AND  DISCOMFORT. 


DEATH    CAMAS    RPK(TES.    ZYfiADENUS   PANICTJLATUS. 


TYPICAL    CASE    OF    CATTLE   863. 

Cattle  863  was  a  steer  in  good  condition,  weighing  457  pounds  at 
the  beginning  of  the  experimental  feeding.  It  was  brought  into  the 
corrals  on,the  afternoon  of  June  30,  1920,  and  re.ceived  no  feed  before 
the  experimental  feeding  of  Z.  paniculatus  was  commenced.  On  July 
3,  at9  .50  a.  m.,  it  was  fed  leaves,  stems,  and  young  fruit  of  Z.  panicula- 
tus, and  received  an- 
other feed  at  5.15  p. 
m.  the  same  day.  At 
9.10  a.  m.,  July  4,  it 
had  eaten  of  the  ma- 
terial 1.109  pounds 
per  hundredweight  of 
animal,  and  refused 
to  eat  more.  At  this 
time  there  were  no 
definite  symptoms  of 
toxic  effect  except  the 
refusal  to  eat.  At 
5.12  p.  m.  it  was 
found  much  salivated 
and  commenced  to 
vomit.  This  vomiting 
continued  at  frequent 
intervals  for  about 
one  hour.  Plate  II, 
figure  5,  shows  the 

animal  in  the  act  of  "vomiting.  No  further  symptoms  were  noted 
except  the  rather  unusually  low  temperature  of  99.9°  F.  at  7.25  a.  m., 
July  5.  At  this  time  the  general  appearance  of  the  animal  was  good, 
and  it  was  turned  into  the  pasture  as  practically  recovered.  Text 
figure  4  shows  the  curve  of  temperature,  indicating  a  depression  as  in 
the  other  cases. 

ACCIDENTAL    CASE    OF   HORSE    137. 

No  experiments  in  feeding  the  plant  to  horses  were  made.  An 
accidental  case,  however,  occurred  which  was  of  considerable  interest 
and  should  perhaps  be  recorded,  since  little  definite  evidence  has  ever 
been  obtained  regarding  the  effects  of  Zygadenus  upon  this  class  of 
animals. 

Horse  137  was  one  of  the  saddle  horses  used  at  the  station.  On 
July  6,  1920,  at  8.15  a.  m.,  it  was  noticed  that  this  animal  was  much 
depressed  and  salivated,  and  saliva  scattered  about  the  corral 
showed  that  this  condition  of  salivation  had  continued  for  some  time. 
While  this  animal  was  a  so-called  gentle  horse,  it  never  readily  per- 
67283°— 22— Bull.  1012 2 


FIG.  4.— Temperature  curve  of  Cattle  863. 


10  BULLETIN"   1012,   U.    S.   DEPARTMENT   OF   AGRICULTURE. 

milled  itself  to  be  bridled  or  handled  in  any  way,  except  when  penned 
up  at  one  corner  of  the  corral.  On  this  morning  it  could  be  approached 
easily  and  did  not  object  to  handling.  The  respiration  was  faster  than 
normal,  and  at  intervals  retching  was  observed.  In  searching  for 
the  cause  of  the  illness  it  was  found  that  the  horse  had  eaten  some  of 
a  mixture  of  Z.  paniculatus  and  hay  that  had  been  thrown  into  the 
corral.  It  was  impossible  to  tell  how  much  he  had  eaten,  so  that 
there  was  no  means  of  telling  what  the  dosage  of  the  plant  had  been. 
The  animal  showed  some  abdominal  discomfort,  and  at  9.30  a.  m. 
he  was  pawing  the  ground  in  a  manner  that  indicated  some  pain. 
His  respiration  was  about  60  a  minute.  During  the  forenoon  this 
condition  continued,  with  prolonged  spells  of  retching,  succeeded  by 
profuse  salivation.  The  animal  did  not  stagger  or  show  any  unusual 
weakness.  This  condition  continued  during  the  forenoon  and  part 
of  the  afternoon,  but  by  4.30  p.  m.  he  had  practically  recovered. 

As  the  horse  was  sick  when  first  seen  in  the  morning  it  was  impossi- 
ble to  tell  how  long  the  illness  continued,  but  it  must  have  been  at 
least  six  hours  and  perhaps  somewhat  longer.  The  case  is  interesting 
because  the  symptoms  were  entirely  comparable  with  those  exhibited 
by  sheep  and  cattle,  but  did  not  continue  to  the  stage  of  weakness. 
Plate  II,  figure  6,  shows  the  attitude  which  the  horse  assumed  during 
the  acute  stage  of  the  illness. 

DISCUSSION  AND  RESULTS. 

SYMPTOMS. 

Salivation. — Salivation  appeared  in  all  the  cases  observed  during 
1919  and  1921,  and  was  the  most  distinctive  symptom.  It  occurred 
in  1920  in  3  of  the  5  cattle  cases,  and  in  11  of  the  13  sheep  cases. 
Salivation  in  most  cases  is  the  first  definite  evidence  of  the  effect 
of  the  plant.  This,  of  course,  can  not  be  considered  as  an  especial 
characteristic  of  Zygadenus  poisoning,  because  it  occurs  in  a  great 
many  forms  of  intoxication  from  plants. 

Nausea. — Nausea  was  exhibited  in  all  the  cases  in  1919.  It  was 
common  in  the  experimental  animals  of  1920  and  1921,  but  did  not 
appear  in  all  cases,  probably  because  the  sickness  was  not  always 
very  pronounced.  Sometimes  it  was  indicated  only  by  regurgita- 
tion.  In  one  of  the  cattle  and  six  of  the  sheep  it  resulted  in  vomiting. 

Weakness. — Muscular  weakness  occurred  in  4  of  the  5  cases  of  1919, 
in  3  of  the  13  sheep,  and  2  of  the  5  cattle  in  1920,  and  in  6  of  the  sheep 
in  1921.  In  all  but  one  of  the  cases  this  weakness  was  most  pro- 
nounced in  the  hind  legs  and  resulted  in  a  characteristic  staggering 
gait.  In  Sheep  569,  which  was  very  sick,  and  in  Sheep  641,  which 
died,  this  weakness  was  so  pronounced  that  they  were  unable  to 
stand.  In  Sheep  583  and  Cattle  784  weakness  was  the  only  symp- 
tom noted  except  a  depression  in  temperature.  This  is  well  shown 
in  Plate  II,  figures  1  to  4,  in  the  case  of  Sheep  569. 


DEATH    CAMAS   SPECIES,   ZYGADENUS   PANICULATUS.  H 

Temperature. — In  the  experimental  work  of  1919,  Cattle  826  was 
the  only  case  in  cattle  that  showed  a  depression  of  temperature.  Of 
the  4  sheep,  3  had  a  low  temperature.  In  1920,  the  5  head  of  cattle 
exhibited  a  lowered  temperature,  and  of  the  13  sheep  all  but  2  showed 
the  same'  effect  of  the  plant.  In  1921,  4  of  the  6  sheep  had  a  lower 
temperature.  This  condition  of  temperature  was  distinct,  but  ordi- 
narily the  temperature  was  not  very  low.  The  lowest  was  98.4°  F., 
which  was  noted  in  two  cases.  One  observation  of  98.8°  F.  was 
made,  two  of. 99°  F.,  and  one  of  99.6°  F.  More  commonly  the 
temperature  did  not  go  below  100°  F.  and  could  not  be  considered 
as  distinctly  subnormal.  There  was,  nevertheless,  in  most  cases,  a 
definite  lowering  of  temperature.  This  is  shown  in  the  temperature 
curves  of  Sheep  602,  Sheep  569,  and  less  markedly  in  Cattle  863.  In 
the  case  of  Sheep  569  a  number  of  temperatures  were  recorded  besides 
those  of  morning  and  night  shown  in  the  diagram,  but  these  addi- 
tional observations  did  not  alter  the  character  of  the  curve. 

In  the  work  carried  on  at  Greycliff,  Mont.,  on  the  Zygadenus  which 
is  stated  in  Bulletin  125  to  be  Z.  venenosus,  and  which  we  are  now 
informed  was  Z.  gramineus,  it  was  noted  that  a  depression  in  tem- 
perature sometimes  appeared  when  no  other  symptoms  were  seen. 
It  was  questioned  whether  the  same  phenomena  might  not  occur  in 
the  cases  receiving  Z.  paniculatus.  The  only  case  of  this  character 
was  Sheep  594,  which  in  5  days,  receiving  2.105  pounds,  had  no 
noted  symptoms  except  a  lowering  of  temperature. 

In  the  discussion  of  the  Montana  work,  in  Bulletin  125,  the  state- 
ment was  made  that  a  low  temperature  coulpl  hardly  be  considered 
as  diagnostic  of  Zygadenus  poisoning.  The  additional  work  which 
has  been  carried  on  with  Z.  paniculatus  shows  that  while  one  or  a 
few  observations  are  not  diagnostic,  if  a  fairly  complete  record  is 
made  after  the  feeding  of  the  plant  to  the  animal,  this  record  when 
plotted  is  pretty  certain  to  indicate  whether  any  toxic  effect  has 
been  produced. 

Pulse. — The  pulse  rate  in  the  sick  sheep  varied  from  52  to  220. 
The  rate  of  220  was  shown  by  Sheep  644,  which  had  pneumonia. 
In  the  sick  cattle  it  varied  from  48  to  210.  This  latter  figure,  how- 
ever, was  observed  in  an  excited  animal  before  the  feeding  of  the 
plant.  The  highest  rate  after  the  feeding  of  the  plant  was  84.  In 
2  or  3  of  the  sheep  the  pulse  rate  was  slightly  higher  during  the  de- 
pression of  temperature,  but  in  most  cases  the  curve  of  the  pulse 
followed  rather  closely  the  curve  of  temperature,  being  low  when 
the  temperature  was  low  and  rapid  when  the  temperature  was  high. 
In  some  cases  it  was  weak  and  in  some  intermittent. 

Respiration. — There  was  some  irregularity  in  respiration,  but  in 
general  the  rate  of  respiration  varied,  much  like  that  of  the  pulse. 
It  was  noted  in  Bulletin  125,  in  regard  to  Z.  gramineus,  that  there 


12 


BULLETIN   1012,    U.    S.    DEPARTMENT    OF   AGRICULTURE. 


was  a  very  high  rate  in  the  acute  stages  of  the  sickness.  That  this 
symptom  did  not  appear  in  the  Z.  paniculatus  cases  may  be  explained 
by  the  fact  that  most  of  the  animals  were  not  very  sick;  that  is,  the 
sickness  could  not  be  considered  as  acute  at  any  time.  It  did  occur, 
however,  in  Sheep  569,  which  was  very  sick.  This  animal,  too, 
as  well  as  Sheep  644  and  647,  exhibited  labored  breathing.  It  may 
be  remarked,  in  this  connection,  that  under  normal  conditions  there 
is  frequently  great  variation  in  the  respiration  of  sheep;  under  excite- 
ment the  rate  may  be  temporarily  very  high. 

Other  symptoms. — Some  of  the  annuals  groaned  and  gnashed  their 
teeth  during  the  sickness,  and  Sheep  569  and  Sheep  647  went  into 
a  condition  of  coma.  Coma  is  also  a  frequent  symptom  in  the 
animals  made  very  sick  by  Z.  gramineus,  as  shown  in  Bulletin  125. 

In  general,  the  symptoms  were  practically  identical  with  those 
seen  in  Z.  gramineus  cases,  but  less  pronounced,  because  of  the 
smaller  toxicity  of  Z.  paniculatus  as  compared  with  Z.  gramineus. 


DURATION    OF    SYMPTOMS. 


The  following  table  shows  the  time  that  elapsed  between  the  first 
and  last  observed  symptoms.  It  should  be  noted  that  this  probably 
does  not  indicate  accurately  the  entire  time  during  which  the  animals 
were  sick,  because  in  many  cases  the  sickness  persisted  for  a  greater 
or  less  time  after  the  last  note  was  made. 

TABLE  2. — Duration  of  symptoms. 


Animal. 

Method  of 
feeding. 

Time  sick. 

Animal.             feeding0                 Time  sick. 

1919. 
Sheep  Nos.: 
528  
530... 

Balling  gun... 
do  

67  hours  5  minutes.  ± 
20  hours  33  minutes  ± 
2  7  hours  40  minutes  ± 
19  hours  8  minutes.  ± 

67  hours  5  minutes. 
20  hours  33  minutes. 
27  hours  40  minutes. 
19  hours  8  minutes. 
24  hours. 
Do. 
7  hours. 
36  hours. 
3  hours. 
Do. 
26  hours. 
29  hours. 
96  hours. 
24  hours. 
60  hours. 
72  hours. 

1919 
Cattle  No.: 
826  Fed  in  hay..,. 

1920. 
Cattle  Nos.: 
874  ...      .  .      do 

Do. 

One  observation. 
96  hours. 
60  hours. 
Salivated;  one  obser- 
vation. 
£  hour. 

One  observation. 
16  hours  18  minutes. 
23  hours  33  minutes. 
42  hours  50  minutes. 
49  hours  16  minutes. 
Death;  sick  72  hours 
43  minutes. 
72  hours  21  minutes. 

555  . 

•  do  

540 

do. 

1920. 
Sheep  Nos.: 
528  
530 

do  
do  

867                   do 

870  !  do  
861...   .  .-   .-do 

863  

1921. 
Sheep  Nos.: 
582  
612 

do  

Balling  gun... 
do 

555  
540.  . 

do  
.      .do  

564  
578  
583  
590 

Fed  in  hay  — 
do  

Balling  gun... 
do  .  . 

593  
599.  .. 

do  
do  

617  

do. 

628 

do 

602 

do 

629  
644  

do  
do 

605  
569.  .  .  . 

do  
do  

647 

do 

575 

do 

609  
583'  

do  
do  

The  average  in  all  the  force-fed  sheep  cases,  25  in  number,  was  36 
hours  and  2J  minutes.  The  minimum  was  a  single  observation  in 
Sheep  582,  and  the  maximum  was  4  days  in  Sheep  569.  Sheep  569 
644,  and  647  were  very  sick,  but  it  is  not  at  all  clear  that  in  other 


DEATH    CAMAS   SPECIES,   ZYGADEXUS   PAXICULATUS. 


13 


cases  the  duration  of  illness  was  correlated  with  the  severity  of  the 
attack. 

Of  the  cattle  it  should  be  noted  that  on  874  and  861  only  a  single 
observation  was  made,  so  that  the  sickness  can  not  be  considered  as 
continuing  an  appreciable  length  of  time.  Of  the  other  cattle,  the 
average  time  of  duration  of  illness  was  57  hours  and  7  minutes,  while 
the  shortest  period  was  30  minutes,  and  the  longest  4  days. 

TIME    REQUIRED   TO    PRODUCE    SYMPTOMS. 

The  cattle  and  two  of  the  sheep  were  given  the  Zygadenus  in  hay, 
so  that  the  feeding  extended  over  a  considerable  period  of  time,  and 
it  would  be  impossible  in  these  cases  to  determine  the  time  between 
the  feeding  and  the  appearance  of  symptoms.  This  can  be  done, 
however,  in  the  animals  that  were  given  a  forced  feeding  by  the  balling 
gun.  The  following  table  shows  the  time  elapsed  in  the  case  of 
these  sheep. 

TABLE  3. —  Time  elapsed  between  feeding  of  plant  and  development  of  symptoms. 


Animal. 

Time  elapsed 
before  symp- 
toms appeared. 

Animal. 

Time  elapsed 
before  symp- 
toms appeared. 

Time  elapsed 
Animal.            before  symp- 
1     toms  appeared. 

1919. 

1920. 

1921. 

Sheep  Nos.: 

Sheep  Nos. 

Sheep  Nos 

528  

3  hours. 

593.  . 

5  hours  30  minutes. 

582.    . 

1  4  hours. 

530  

1  hour  47  minutes. 

599. 

3  hours. 

612. 

4  hours  44  minutes. 

555  

2  hours  33  minutes. 

602. 

Do. 

617. 

2  hours  5  minutes. 

540  

2  hours  12  minutes. 

609. 

55  minutes. 

628. 

50  minutes. 

609. 

3hrs. 

629. 

1  hour  38  minutes. 

1920. 

569. 

2  hours  15  minutes. 

644.. 

1  hours  42  minutes. 

Sheep  Nos.: 

575. 

4  hours  30  minutes. 

647.. 

2  hours  2  minutes. 

583  

22  hours  7  minutes. 

609. 

8  hours  40  minutes. 

V590  

3  hours. 

583.. 

2hrs. 

The  time  elapsing  varied  between  50  minutes  in  the  case  of  Sheep 
628,  and  22  hours  and  7  minutes  in  the  case  of  the  first  experiment 
with  Sheep  583.  In  this  case,  however,  it  is  probable  that  the  time 
is  very  much  too  long,  because  no  observation  was  made  upon  the 
animal  from  4.47  p.  m.,  June  21,  to  9.22  a.  m.,  June  22.  It  is  to  be 
presumed  that  the  animal  was  sick  during  the  night.  Excluding  this 
animal,  the  maximum  time  elapsing  was  8  hours  and  40  minutes,  in 
the  second  poisoning  case  of  Sheep  609.  Excluding,  too,  the  case 
of  Sheep  583,  the  average  of  all  these  sheep  cases  was  2  hours  and  58 


minutes. 


TOXIC    AND    LETHAL    DOSAGE. 


It  is  evident  that  a  number  of  factors  may  affect  the  toxic  dosage 
of  any  plant.  Most  prominent  among  these  factors  are  the  method 
of  feeding,  the  age  of  the  plant,  the  part  of  the  plant  used,  and  the 
kind  of  animal  used  for  experimental  purposes.  Any  figures  in  regard 
to  dosage  may  have  a  considerable  margin  of  error,  as  very  few 
animals  are  subject  to  experiment  under  exactly  the  same  conditions. 


14  BULLETIN   1012,    U.    S.    DEPARTMENT   OF  AGRICULTURE. 

Efect  of  method  of  feeding. — Two  methods  of  feeding  were  used 
with  the  experimental  animals,  forced  feeding  with  the  balling  gun 
and  feeding  the  plant  mixed  with  hay. 

Only  two  sheep,  Nos.  564  and  578,  were  made  sick  by  feeding  the 
plant  with  hay.  They  were  fed  leaves,  stems,  and  buds.  The 
smallest  effective  dose  of  leaves,  stems,  and  buds  when  fed  by  the 
balling  gun,  is  1.096  pounds.  The  smallest  dose  of  the  two  animals 
fed  in  hay  was  0.284  pound  in  the  case  of  Sheep  564.  Apparently 
the  animals  fed  with  hay  were  made  sick  on  a  smaller  dosage.  There 
is  some  doubt,  however,  in  regard  to  the  accuracy  of  the  dosage  fig- 
ures in  the  case  of  Sheep  564.  Five  head  of  cattle  were  given  the 
plant  in  hay,  with  a  minimum  dosage  of  0.264  pound. 

Influence  of  age  of  the  plant. — It  was  at  first  thought  that  the  collec- 
tions early  in  the  season  were  somewhat  more  toxic  than  those 
obtained  later.  A  careful  examination  of  the  cases,  however,  does 
not  bear  this  out.  So  far  as  present  evidence  is  concerned,  then, 
the  plant  is  nearly  equally  toxic  at  all  seasons. 

Comparative  toxicity  of  parts  of  the  plant. — An  examination  of  the 
dosage  (Table  1)  shows  very  clearly  the  extreme  toxicity  of  the  seed. 
The  fruit  heads  stand  next,  while  there  is  no  evidence  to  show  any 
material  difference  in  the  toxicity  of  the  other  parts  of  the  plant. 
It  should  be  stated,  however,  that  of  course  the  weight  of  seed  is  of 
dry  material,  while  the  weights  of  the  other  parts  of  the  plant  are  of 
green  material.  It  would  follow,  then,  that  the  difference  between  the 
toxicity  of  the  seed  and  the  other  parts  of  the  plant  is  not  so  great 
as  the  table  indicates. 

Effect  on  different  animals. — Only  two  classes  of  animals,  cattle 
and  sheep,  were  used  in  these  experiments,  and  most  of  the  sheep 
were  fed  by  the  balling  gun.  Comparing  Cattle  861  and  863,  which 
received  leaves,  stems,  and  young  fruit,  with  Sheep  583,  590,  599, 
602,  and  605,  which,  were  made  sick  on  similar  material,  it  appears 
that  the  plant  is  about  twice  as  toxic  for  cattle  as  for  sheep.  This, 
if  true,  is  an  interesting  fact,  but  probably  not  of  any  especial  practi- 
cal importance,  as  there  is  no  reason  to  think  that  cattle  on  the  range 
eat  much  of  this  plant. 

As  a  general  statement  regarding  the  toxicity  of  Z.  paniculatus  it 
would  probably  be  safe  to  say  that,  excluding  the  fruit  and  the  seed, 
the  toxic  dose  of  the  plant  is  between  1  and  2  pounds  per  hundred- 
weight of  animal. 

Fleming  3  gives  as  minimum  toxic  doses  for  yearling  calves  three- 
eighths  of  a  pound,  and  with  regard  to  sheep  states  that  less  than 
one-fourth  of  a  pound  rarely  produces  poisoning  symptoms,  and  in  a. 

3  Annual  Report  of  the  Board  of  Control  for  the  fiscal  year  ending  June  30, 1919.  Agricultural  Experi- 
ment Station,  University  of  Nevada,  Department  of  Range  Management.  1920,  pp.  42-43. 


DEATH    CAMAS   SPECIES,   ZYGADENUS   PANICULATUS.  15 

few  cases  over  1  pound  has  been  fed  with  negative  results.  Sheep 
most  frequently  have  been  made  sick  with  amounts* in  excess  of  1 
pound,  while  most  of  the  deaths  have  resulted  from  If  to  4  pound 
feedings.  Fleming  does  not  give  the  weights  of  the  animals.  If  it 
is  assumed,  however,  that  his  sheep  weighed  100  pounds  each,  his 
figures  for  sheep  would  not  differ  widely  from  those  obtained  by  us. 
If  his  yearling  calves  were  well  grown,  his  figures  for  cattle  would  be 
much  smaller  than  those  in  this  paper.  In  any  case,  he  seems  to 
have  found  the  plant  much  more  toxic  for  cattle  than  for  sheep, 
thus  far  confirming  the  apparent  result  of  the  work  reported  here. 

Toxic  dose  of  Z .  paniculatus  compared  with  Z.  gramineus. — It  is  diffi- 
cult to  make  anything  like  an  exact  comparison  of  the  present  results 
with  those  given  in  Bulletin  125  for  Z.  gramineus,  because  the  experi- 
ments on  Z.  gramineus  were  not  very  carefully  checked  up  with 
regard  to  loss  of  moisture.  The  Z.  gramineus,  however,  was  ordi- 
narily used  fresh,  so  that  this  difference  is  not  so  great  as  it  otherwise 
would  be.  In  the  case  of  Z.  paniculatus,  as  quoted  in  the  bulletin, 
the  material  used  was  several  days  old,  and  without  doubt  the  dosage 
would  be  multiplied  by  four  to  bring  the  figures  to  green  weight. 
As  compared  with  Z.  gramineus,  the  seeds  and  fruit  heads  of  Z. 
paniculatus  are  fully  as  toxic,  but  the  other  parts  of  the  plant  are 
much  less  toxic.  The  work  with  Z.  gramineus  showed  that  in  a 
general  way  the  toxic  dose  was  about  0.5  pound,  while  the  work 
with  Z.  paniculatus,  as  stated  above,  indicates  that  in  a  general  way 
the  toxic  dose  is  between  1  and  2  pounds,  or  it  may  be  said  that  Z. 
gramineus  is  approximately  three  times  as  poisonous  as  Z.  pani- 
culatus. 

Lethal  dosage. — Only  one  death  occurred  during  the  experimental 
work  with  Z.  paniculatus,  that  of  Sheep  644,  on  2.5  pounds,  and  this 
animal  suffered  from  pneumonia.  That  it  will  and  does  kill  under 
range  conditions,  however,  is  abundantly  proved  by  many  well- 
authenticated  cases. 


LOSSES    FROM    Z.    PAXICULATUS. 


The  stockmen,  of  course,  make  no  distinction  between  the  species 
of  death  camas.  Moreover,  the  systematic  botanists  are  by  no  means 
agreed  as  to  the  determination  of  species  or  the  names  which  should 
I  be  applied  to  them.  This  confusion  makes  it  difficult  to  state  defi- 
nitely whether  reported  losses  from  death  camas  should  be  ascribed 
to  one  species  rather  than  another.  From  the  distribution  of  Z. 
paniculatus,  as  given  on  page  3,  it  may  be  assumed  that  most  of  the 
death-camas  losses  in  Utah,  Nevada,  Idaho,  and  eastern  Oregon  are 
caused  by  this  species.  These  losses  have  been  very  heavy. 


16 


BULLETIN   1012,    U.    S.    DEPAKTMEXT   OF   AGRICULTURE. 


ZYGADENUS  ELEGANS. 

DESCRIPTION  AND  DISTRIBUTION  OF  THE  PLANT.* 

Zygadenus  elegans,  shown  in  Plate  III,  is  an  erect  perennial  herb 
with  leafy  stems  arising  from  coated  bulbs.  Often  numerous  bulbs 
are  together,  forming  clumps;  three  are  so  grouped  in  the  picture. 
The  linear  grasslike  leaves  are  one-sixth  to  one-half  inch  broad,  4  to  12 
inches  long,  and  are  much  whitened,  particularly  when  young;  the 
lower  ones  are  sheathing  at  base,  the  upper  without  sheaths. 

The  flowers  are  in  racemes  which  are  simple  or  somewhat  branched 
below,  and  often  few-flowered.  Under  the  flowers  are  ovate-lanceo- 
late purplish  bracts. 
The  greenish  straw- 
colored  or  whitish 
flower  segments  are 
one-fourth  to  five- 
twelfths  of  an  inch  in 
length  and  adhere  to 
the  base  of  the  ovary. 
The  glands  of  the 
upper  flower  segments 
are  obcordate.  The 
ovary  is  ovate  in  form 
and  the  stamens  are 
included. 

In  the  western  part 
of  the  United  States 
(figure  5)  this  plant 
ranges  from  the 
Olympic  Mountains, 
Washington,  east  to 
central  Montana  and 
southward  through 
central  Oregon  and 
central  Nevada  to  southern  Arizona  and  east  to  central  New  Mexico. 
In  this  region  it  is  a  high-mountain  plant  ranging  from  2,500  to 
13,000  feet.  The  natural  habitat  of  Z.  elegans  is  moist  meadows  and 
springy  places  from  the  yellow-pine  to  the  arctic-alpine  zones.  'Near 
the  Salina  Experiment  Station  the  plant  buds  early  in  July,  is  in  flower 
from  the  middle  of  July,  and  seeds  in  August  and  September. 

Distinction  between  Z.  paniculatus  and  Z.  elegans. — The  technical 
description  already  given  will  serve  to  distinguish  clearly  the  two 
species  treated  of  in  this  bulletin.  The  stockman,  however,  using 
the  country  within  the  range  of  these  plants,  can  readily  separate 

*  The  description  of  Z.  elegans  and  its  distribution  was  prepared  by  W.  W.  Eggleston,  of  the  Bureau  of 
Plant  Industry,  U.  S.  Department  of  Agriculture. 


FIG.  5.— Distribution  of  Zygadenus  elegans  in  the  western  part  of  the 
United  States. 


Bui.  1012,  U.  S.  Dept.  of  Agriculture. 


PLATE  III 


ZYGADENUS  ELEGANS.   THREE  PLANTS  GROWING  TOGETHER.   THE  DRIED  STEM 
OF  THE  PLANT  OF  THE  PRECEDING  YEAR  is  ALSO  SHOWN. 


DEATH    CAMAS   SPECIES,   ZYGADENUS  PANICULATUS.  17 

them  by  their  general  appearance  and  habits.  Z.  paniculatus  has 
thick,  spreading  leaves,  while  Z.  elegans  has  thin,  grasslike  leaves. 
Z.  paniculatus  grows  in  dry,  somewhat  exposed  places  at  elevations 
not  exceeding  about  8,500  feet.  Z.  elegans  grows  in  damp  places 
in  meadows,  or  along  small  streams,  sometimes  actually  in  the  water, 
at  others  on  shady,  damp  hillsides,  and  generally  in  the  western 
mountains  at  elevations  above  8,000  feet.  So  far  as  the  western 
ranges  are  concerned,  Z.  elegans  might  be  called  the  mountain  camas. 

EXPERIMENTAL  FEEDING. 

Experimental  feedings  of  Z.  elegans  to  sheep  were  made  in  the 
summers  of  1915, 1917, 1918, 1920,  and  1921.  No  definite  results  were 
obtained  in  1915  and  1918.  It  appeared  later  that  the  dosage  in 
most  of  these  cases  was  too  small  to  produce  intoxication.  Inasmuch 
as  during  these  two  years  exact  data  regarding  loss  of  moisture  in  the 
plants  used  were  not  recorded,  the  results  can  not  be  compared  with 
those  of  1917,  1920,  and  1921,  and  it  seemed  best  not  to  include  these 
experiments  in  the  summarized  statement  of  Table  6.  In  1917  there 
were  11  experimental  feedings  of  sheep,  8  animals  being  more  or  less 
affected.  In  1920  there  were  21  experimental  feedings,  resulting  in 
9  cases  of  poisoning  and  1  death.  In  1921  there  were  8  feedings,  with 
2  cases  of  poisoning.  Table  6  gives  a  summarized  statement  of  the 
cases  of  these  three  years. 


18 


BULLETIN  1012,   U.    S.   DEPARTMENT  OF  AGRICULTURE. 


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DEATH   CAMAS   SPECIES,    ZYGADENUS   ELEGANS. 


19 


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20  BULLETIN   1012,    U.    S.    DEPARTMENT  OF   AGRICULTURE. 

TYPICAL    CASE    OF   SHEEP   588. 

In  most  of  the  cases  the  symptoms  were  neither  very  acute  nor 
very  prolonged.  Sheep  588  may  be  considered  fairly  typical  of  one 
of  the  more  pronounced  cases.  This  sheep  was  a  yearling  wether 
weighing  101.25  pounds  at  the  time  of  the  experiment.  It  was 
taken  into  the  corrals  for  observation  on  the  morning  of  July  17, 
1920.  The  experimental  feeding  was  commenced  July  19,  1920. 
On  account  of  the  large  quantity  necessary  to  produce  toxic  effect, 
the  plant  was  administered  in  several  doses.  At  10.57  a.  m.  200 
grams  of  stems,  leaves,  and  flowers  of  the  plant  were  given.  The 
sheep  was  somewhat  salivated  as  the  result  of  this  feeding,  but  no 
further  symptoms  developed  during  the  administration  of  the  plant. 
Other  feedings  were  made  at  11.15  a.  m.,  11.37  a.  m.,  11.51  a.  m., 
11.57a.m.,  12.06p.m.,  12.22.  pm.,  1.10p.m.,  and  1.20  p.  m.  At  these 
feedings  quantities  varying  from  100  to  200  grams  were  given.  The 
feeding  in  each  case  occupied  about  five  minutes.  All  told,  the 
animal  received  an  equivalent  of  2.939  pounds  of  green  plants  to  100 
pounds  of  animal. 

No  symptoms  were  noted  until  4.24  p.  m.  At  that  time  the  sheep 
was  regurgitating  and  frothing  at  the  mouth.  The  temperature  was 
102.8°  F.,  pulse  100,  respiration  72.  At  5.30  p.  m.  the  animal  was 
still  badly  salivated,  and  was  standing  with  the  hind  legs  braced 
back  and  head  held  rather  high.  The  respiration  was  fast  and  deep. 
At  5.55  p.  m,  the  animal  showed  unsteadiness  when  attempting  to 
walk.  There  was  at  this  time  distinct  hyperesthesia;  it  was  startled 
by  sudden  noises  or  by  being  touched.  The  condition  remained 
the  same  during  the  evening.  Observations  continued  until  10.30 
p.  m.  The  salivation  continued  and  the  animal  was  unsteady  on  its 
feet,  and  occasionally,  when  startled,  would  fall  down  but  was  able  to 
get  upon  its  feet  again.  At  9.45  p.  m.  and  10.30  p.  m.  it  was  found  lying 
down  but  got  up  readily,  although  its  gait  when  walking  was  very 
unsteady. 

On  July  20,  at  7.10  a.  .m.,  when  observed  it  was  still  salivated, 
was  quiet  and  depressed,  but  much  stronger  than  the  night  before. 
During  the  day  the  condition  of  the  animal  improved  gradually  and 
on  the  morning  of  July  21  it  was  turned  into  the  pasture,  as  it  seemed 
to  have  recovered  completely. 

DISCUSSION  AND  RESULTS. 

SYMPTOMS. 

Salivation. — Salivation  occurred  in  all  but  2  of  the  cases.  There 
was  evidence  of  nausea  in  6  cases.  In  some  of  these  cases  this  was 
shown  by  more  or  less  regurgitation.  Actual  vomiting  occurred  in 
5  animals. 


DEATH  CAAIAS  SPEC'IES.  ZYGADEXUS  ELEGAXS. 


21 


Weakness. — Pronounced  weakness  was  noted  in  14  of  the  animals. 

Temperature. — There  was  no  evidence  of  any  effect  oij  temperature. 
In  this  connection  perhaps  it  should  be  noted  that  none  of  the  animals, 
with  the  exception  of  Sheep  599,  were  very  sick,  and  few  temperature 
observations  were  made  on  this  animal. 

Pulse.— No  effect  on  the  pulse  was  noted. 

Respiration. — Sheep  599,  which  was  very  sick  and  died,  had  an 
irregular  respiration  that  at  times  was  labored.  Irregular  respiration 
was  noted  in  Sheep  625.  In  other  cases  labored  respiration  was 
noted. 

Trembling  and  heightened  reflexes. — It  is  interesting  to  note  that  2 
animals,  Sheep  588  and  599,  exhibited  hyperesthesia,  and  one,  Sheep 
599,  showed  muscular  trembling.  These  symptoms  were  noted 
quite  generally  in  the  Z.  gramineus  cases  seen  in  Montana,  but  were 
not  seen  in  the  Z.  paniculatus  animals. 

In  general,  the  symptoms  closely  resembled  those  seen  in  the 
effects  of  the  other  species  of  Zygadenus,  differing  only  in  degree. 


DURATION    OF    SYMPTOMS. 


Table  7  shows  the  time  during  which  the  symptoms  continued. 
As  in  the  similar  table  for  Z.  paniculatus,  the  time  was  computed 
from  the  first  noted  symptom  to  the  last  observation. 

TABLE  7. — Duration  of  symptoms. 


Animal. 

Duration  of  illness. 

Animal. 

Duration  of  illness. 

Sheep  Nos.: 
450 

Sheep  Nos.  —  C'outd. 
580  

5  hours. 

441 

585 

1  observation. 

445 

do 

588  

15  hours. 

444 

599  

6^  hours  to  death. 

445 

10  minutes 

604  

20  hours. 

449 

1  2£  hours. 

564  

3  hours. 

4cc 

569 

Do. 

455 

'        do. 

530  

4^  hours. 

571 

!  i  hour 

625  

20  hours,  6  minutes. 

574  

..  J  1  observation. 

li'24  

11  hours,  19  minutes. 

1 

The  average  time  of  all  the  cases  was  5  hours  and  17  minutes. 
Sheep  599,  which  died,  was  sick  6J  hours.  The  shortest  periods  of 
illness  were  those  in  which  a  single  observation  was  made;  the  longest 
was  20  hours  and  6  minutes. 

As  compared  with  Z.  panic-Hiatus  the  sickness  was  of  shorter 
duration. 

TIME    REQUIRED    TO    PRODUCE    SYMPTOMS. 

Table  8  states  the  time  elapsing  between  the  feeding  of  the  plant 
and  the  development  of  symptoms.  In  some  of  these  cases  repeated 
feedings  were  made,  so  that  the  administration  of  the  plant  extended 
over  a  considerable  period  of  time.  In  Sheep  588,  for  example,  the 
plant  was  given  in  9  feedings  involving  a  period  of  3  hours.  The 


22  BULLETIN    1012,    1*.    S.    DEPARTMENT   OF   AGRICULTURE. 

times  given  in   the   table   are   computed   from   the   time   when   the 
feedings  were  finished. 

TABLE  S.—  Time  elapsed  from  feeding  to  development  of  symptoms. 


Animal.  Time.  Animal.  Time. 


Sheep  Is  os.: 
450 

Immediately 

Sheep  Nos.—  Contd. 
580  

Immediately. 

441  

5  minutes. 

585  

6  hours. 

445                    -  - 

12  minutes. 

588  

3  hours. 

444 

28  minutes 

599              

8  minutes. 

445 

604 

2  hours  24  minutes 

449 

14  hours  55  minutes 

564       

2  hours,  36  minutes 

455 

569 

Immediately 

455                

do. 

580  

5  hours. 

571 

5  hours. 

625  

10  minutes. 

574  

7  hours. 

624  

7  hours,  37  minutes. 

In  some  of  the  animals  the  symptoms  followed  immediately  after 
the  feeding.  The  longest  time  before  symptoms  was  14  hours  and 
55  minutes  in  the  case  of  Sheep  449.  This  probably  is  longer  than 
the  actual  time,  for  the  symptoms  were  first  noted  in  the  morning 
and  it  is  probable  that  the  animal  had  been  sick  during  the  night. 
Excluding  Sheep  449  the  average  time  elapsing  between  the  feeding 
and  the  development  of  symptoms  was  2  hours  and  5  minutes.  On 
the  average  the  symptoms  appeared  somewhat  more  quickly  than 
was  the  case  with  Z.  paniculatit*. 

RESULT  OF    AUTOPSYS. 

Opportunity  was  found  for  only  one  autopsy,  that  on  Sheep  599. 
In  this  animal  the  left  ventricle  was  contracted  and  the  right  expanded. 
The  left  lung  was  highly  congested,  and  the  right  lung  congested  to 
the  point  of  hepatization.  The  extreme  condition  of  the  right  lung 
was  probably  due  to  hypostasis.  No  other  abnormal  conditions 
were  noticed. 

TOXIC   AND   LETHAL    DOSAGE. 

Table  6  shows  the  dosage  of  the  animals  poisoned  in  1917,  1920, 
and  1921. 

To  determine  the  probable  toxic  dosage  of  the  plant  it  is  necessary, 
of  course,  to  consider  only  the  minimum  quantities  required  to  pro- 
duce intoxication  or  death. 

It  should  be  noted  in  connection  with  this  table  that  although  both 
seeds  and  fruit  heads  were  used,  no  results  were  obtained  from  the 
dosage  used  from  these  parts  of  the  plant.  Sheep  630  received  0.807 
pound  of  seed  with  no  effect,  and  Sheep  594  received  2.437  pounds 
of  fruit  heads  with  no  effect. 

So  far  as  Table  6  is  concerned,  it  appears  that  in  general  terms  the 
toxic  dose  of  Z.  elegans  varies  from  2  to  4  pounds  per  100  pounds  of 
animal. 

Lethal  dose. — Only  one  animal,  Sheep  599,  was  killed  by  Z.  elegans. 
The  quantity  used  in  this  case  was  6.153  pounds  of  leaves,  stems,  and 


DEATH    ('A.MAS    SPECIES,    XVCADEXTS    KLKCAXS.  23 

flowers.  Sheep  455  received  5.625  pounds  of  leaves,  si  cms,  and 
flowers  with  the  result  that  only  symptoms  were  produced.  It  seems 
fair  to  presume  that  the  lethal  dose  is  about  6  pounds  per  100  pounds 
of  animal. 

Comparative  toxicity  of  different  part*  of  iltc  plant. — The  dosages 
shown  in  the  table  do  not  give  any  clear  indication  regarding  the 
relative  toxicity  of  different  parts  of  the  plant.  It  appears  probable, 
however,  that  the  stems  are  less  toxic  than  the  other  parts  of  the 
plant,  that  the  bulbs  are  certainly  no  more  toxic  than  the  other 
parts,  and  that  the  plant  is  possibly  somewhat  more  poisonous  in  the 
bud  stage  than  later  in  the  season. 

Probably  no  cumulative  effect. — In  1915  Sheep  334  received  for  13 
days  an  average  daily  dose  of  1  pound  of  leaves,  stems,  buds,  and 
flowers.  The  feeding  was  commenced  July  16  and  terminated  on 
July  29,  when  the  animal  died  from  choking.  The  animal  was  sali- 
vated July  17,  19,  and  20  and  seemed  somewhat  depressed.'  These 
symptoms,  however,  did  not  increase  in  the  succeeding  days.  In 
fact,  after  July  20  no  symptoms  were  noticed  except  slight  depression. 

In  1919  Sheep  453  received  for  seven  days  .an  average  daily  dose  of 
2.361  pounds  of  leaves,  stems,  and  flowers  with  no  effect.  In  this 
same  year  Sheep  455  received  5.625  pounds  of  leaves,  stems,  and 
flowers  on  one  day  and  on  the  succeeding  day  2.475  pounds.  The 
sheep  exhibited  symptoms  on  both  days,  but  was  not  seriously  af- 
fected, although  the  dose  of  the  first  day  was  very  large,  and  that  of 
the  second  greater  than  the  minimum  toxic  dose.  These  experi- 
ments were  not  numerous  enough  to  form  the  basis  for  a  dogmatic 
statement,  but  they  are  nevertheless  significant,  and  indicate  the 
probability  that  there  is  little,  if  any,  cumulative  effect  in  poisoning 
by  Z.  elegans. 

Comparison  of  dosage  with  that  of  Z.  elegans  in  1913. — In  Bulletin 
125  wras  reported  the  poisoning  of  two  experimental  sheep  at  Grey- 
cliff,  Mont.,  by  Z.  elegans  obtained  from  the  Beartooth  National  For- 
est. It  was  stated  that  Sheep  199  showed  symptoms  from  0.44 
pound  of  leaves,  stems,  flowers  and  some  fruit,  and  that  Sheep  185 
showed  slight  sickness  from  0.66  pound  of  leaves,  stems,  flowers  and 
some  fruit.  Apparently  this  is  a  very  much  smaller  dosage  than  that 
in  the  present  work  at  the  Salina  Experiment  Station.  In  the  experi- 
ments with  this  plant  at  Grey  cliff,  Mont.,  however,  no  account  was 
made  of  the  loss  of  weight  by  drying.  In  all  the  later  work  careful 
drying  experiments  have  been  made  and  it  has  been  found  that  the 
plants  suffer  a  surprising  loss  of  moisture  in  a  short  time.  The 
Beartooth  National  Forest  material  was  collected  July  20,  1913,  and 
used  July  2.8.  We  now  know  that  it  must  have  lost  at  least  75  per 
cent  of  its  weight  in  that  time,  so  that  if  we  estimate  the  dosage  in 


24 


BULLETIN   1012,    U.    S.    DEPARTMENT    OF   AGRICULTURE. 


green  weight  the  figures  for  the  dosage  of  Sheep  199  and  185  should 
be  multiplied  by  four.  This  makes  the  dosage  compare  fairly  well 
with  the  1920  experiments. 

COMPARATIVE  TOXICITY  OF  Z.   GRAMINEUS  Z.  PAXICULATUS,   AXD  Z.   ELEGANS. 

From  the  somewhat  insufficient  data  of  the  experimental  work 
there  have  been  tabulated  the  smallest  effective  doses  in  sheep  of  the 
three  species  of  Zygadenus  which  have  been  examined.  All  these 
cases  were  of  forced  feedings  with  the  exception  of  the  feeding  of 
seed  of  Z.  gramineus. 

TABLE  11.— Comparative  toxicity  of  Z.  gramineus,   Z.   paniculatus,   and  Z.   elegans; 

minimum  effective  dosage. 


Part  of  plant. 

Z.  grami- 
neus. 

Z.  panicu- 
latus. 

Z.  elegans. 

Leaves,  stems,  and  young  fruit 

Pound. 
0.  7.37 

Pounds. 
1.505 

Pounds. 

Leaves  and  steins  

.33 

1.984 

3.  74S 

Fruit  heads. 

.141 

.62 

Seed  

1.092 

.07 

Leaves,  stems,  and  buds  . 

.495 

1.096 

1.97 

Leaves,  stems,  and  flowers 

2  939 

Leaves'  stems'  flowers  and  buds 

495 

Leaves,  stems,  flowers,  and  bulbs    . 

2.373 

i  Fed. 

Table  11  shows  those  cases  which  received  similar  material.  It  is 
impossible,  of  course,  to  determine  from  a  table  of  this  character  the 
relative  toxicity  of  the  plants  with  any  degree  of  exactness.  It  ap- 
pears, however,  that,  put  in  a  general  way,  Z.  gramineus  is  three 
times  as  toxic  as  Z.  paniculatus,  and  seven  times  as  toxic  as  Z.  elegans. 
It  is  interesting  to  note  that,  so  far  as  the  experiments  are  concerned, 
the  toxicity  of  the  seed  of  Z.  gramineus  and  Z.  paniculatus  is  practi- 
cally the  same. 

COMPARATIVE  TOXICITY  OF  FRUIT  AXD  SEEDS  OF  Z.  PAXICULATUS  AXD  Z.   ELEC1AXS. 

Ripe  fruit  heads  of  both  Z.  paniculatus  and  Z.  elegans  were  col- 
lected and  the  seed  separated  from  the  pods  and  weighed.  In  both 
species  it  was  found  that  very  close  to  one-half  of  the  dry  weight  was 
seed.  In  one  collection  of  nearly  ripe  Z.  elegans  the  fruit  heads  were 
weighed  separately  from  the  rest  of  the  plant  and  found  to  be  23.4 
per  cent  of  the  entire  plant  exclusive  of  the  bulbs  and  roots.  From 
this  it  appears  that  in  Z.  elegans  close  to  11.7  per  cent  of  the  weight 
of  mature  air-dried  plant  is  seed. 

The  comparative  toxicity  of  fruit  heads  and  seed  of  Z.  paniculatus 
shows  that  most  of  the  toxic  element  of  the  fruit  heads  is  in  the  seed. 
Sheep  569  was  made  very  sick  on  0.661  pound  of  green  fruit  heads,  a 
sample  of  which  lost  77  per  cent  in  drying.  This,  then,  was  equiva- 
lent to  0.152  pound  of  dry  material.  Sheep  609  was  made  sick  on 
0.124  pound  of  dry  fruit  heads.  Sheep  583  was  made  very  sick  on 


DEATH    CAA1AS    SPKCIKS,    XVCADKXl'S    KLKdANS.  25 

0.07  pound  of  seeds,  or  almost  exactly  one-half  the.  dose  of  the  whole 
fruit  head. 

Drying  experiments  make  it  possible  to  figure  the  doses  of  various 
parts  of  the  plant  given  in  terms  of  dry  material.  Inasmuch  as  the 
seeds  fed  were  dry,  this  is  desirable  in  making  comparisons  of  relative 
toxicity  of  seeds  and  other  portions  of  the  plant.  When  this  is  done 
it  appears  that  with  Z.  paniculatus  the  seeds  are  twice  as  toxic  as  the 
fruit  heads  and  four  times  as  toxic  as  leaves,  stems,  and  flowers,  while 
the  fruit  heads  are  about  twice  as  toxic  as  leaves,  stems,  and 
flowers.  That  this  ratio  does  not  hold  with  Z.  elegans  is  shown  by 
the  feeding  of  0.463  pound  of  dry  fruit  heads  and  0.807  pound  of  seed 
without  effect  when  0.623  pound  was  found  to  be  a  toxic  dose  of  dry 
leaves,  stems,  and  flowers.  In  other  words,  fruit  heads  or  seeds  of 
Z.  elegans  are  little  if  any  more  toxic  than  leaves,  stems,  and  flowers. 

Z.   ELEGANS  NOT   ESPECIALLY    DANGEROUS  FOR  SHEEP. 

If  sheep  were  to  graze  on  Z.  elegans  they  would  rarely  get  the 
bulbs,  although  these  can  sometimes  be  pulled  up,  as  the  plant  grows 
in  wet  ground  and  the  bulbs  are  not  far  from  the  surface.  The  feed- 
ing would  be  largely  on  the  aerial  parts  of  the  plant,  and  of  these  it  is 
thought  that  the  fruit  and  seeds  would  seldom  be  eaten,  as  they  are 
dry  and  unattractive.  Of  the  parts  of  the  plant  likely  to  be  eaten  it 
would  take  from  1.5  pounds  to  between  3  and  4  pounds  per  100  pounds 
of  animal  to  poison  an  animal  and  6  pounds  to  produce  a  fatal  effect. 
It  follows  that  poisoning  from  Z.  elegans  is  not  likely  to  occur,  as 
sheep  would  seldom  eat  so  large  a  quantity.  Moreover,  Z.  elegans 
grows  in  localities  where  there  is  ordinarily  an  abundance  of  vegeta- 
tion, so  that  animals  would  not  be  forced  to  eat  it  because  of  a  lack 
of  other  forage.  While  both  Z.  gramineus  and  Z.  paniculatus  may 
and  do  cause  losses,  Z.  elegans  can  be  hardly  be  reckoned  as  an  impor- 
^  tant  poisonous  plant;  in  fact,  it  is  doubtful  whether  it  causes  any 

:   losses  on  the  range. 

SUMMARY. 

1.  In  preceding  investigations  of  the  species  of  Zygadenus,  known 
popularly  under  the  collective  name  of  "  death  camas,"  little  atten- 
tion has  been  given  to  the  comparative  toxicity  of  the  various  species. 

2.  Detailed  studies  of  Z.  paniculatus  and  Z.  elegans,  compared  with 
preceding  work  with  Z.  gramineus,  have  shown  a  marked  difference  in 

toxicity. 

3.  Z.  paniculatus  is  found  to  be  about  one- third  as  toxic  as  Z. 
gramineus,  and  Z.  elegans  about  one-seventh. 

4.  While  Z.  paniculatus  is  not  so  toxic  as  Z.  gramineus,  it  is  a 
distinctly  dangerous  plant,  and  is  the  cause  of  heavy  losses  of  live- 
stock.    Z.  elegans,  however,  while  it  may  poison  livestock,  probably 
does  little  or  no  damage  under  practical  range  conditions. 


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PAT.  JAN.  21,  1908 


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